The nerve conduction study is normal aside from a L.ulnar neuropathy at the elbow and mildly reduced L.tibial CMAP amplitude. The needle EMG is predominantly myopathic (early recruitment or small, polyphasic motor units in rectus femoris and iliopsoas). Reduced recruitment noted in the L.vastus medianlis in the absence of neurogenic units is of unclear significance. Large motor units and reduced recruitment in the FDI ould be the result of ulnar neuropathy. What is the differential diagnosis?